Syringe

ABSTRACT

A syringe with which an accurate amount of a liquid can be discharged by a simple operation. 
     The syringe  1  includes an outer tube  2 , a gasket  3  slidable in the outer tube  2 , a pusher  4  operable for moving the gasket  3 , and a stopper  5  disposed to be slidable along the longitudinal direction of the pusher  4 . The stopper  5  is fixed relative to the pusher  4  by the engagement of engaging portions, provided therein, with racks  47   a,    47   b  formed on the pusher  4 . When an operating portion  71  is depressed, the fixation condition is released, permitting regulation of the position of the stopper  5  on the pusher  4 . When the depression on the operating portion  71  is canceled, the fixation condition is retained. When the pusher  4  is pressed in the tip end direction, a tip end face  66  of the stopper  5  comes into contact with a base end portion  28  of the outer tube  2 , whereby the depth of insertion of the pusher  4  into the outer tube  2  is restricted, and a set amount of a chemical  100  is discharged through a diameter-reduced portion  22.

TECHNICAL FIELD

The present invention relates to a syringe with which an accurate amountof a liquid can be discharged through a simple operation.

BACKGROUND ART

A syringe comprises an outer tube, a gasket inserted in the outer tube,and a pusher (plunger rod) connected to the gasket, and is used todischarge a liquid such as a chemical by pressing the pusher to slidethe gasket in the outer tube toward the tip end thereof.

In this case, for discharging an accurate amount of the liquid, it isnecessary to regulate the amount of movement of the gasket while lookingat the graduations provided on the outer circumferential surface of theouter tube and to carefully operate the pusher.

In cases of the conventional syringes, however, the problem that theamount of the liquid discharged would be too large or too small isliable to be generated due to a misoperation (overpushing orinsufficient pushing) of the pusher or misreading of the graduations.

As a syringe for solving such a problem, syringes in which the amount ofmovement of the pusher can be restricted have been proposed, forexample, in Japanese Utility Model Publication No. Hei 2-15502 andJapanese Utility Model Laid-open No. Sho 62-119944.

In the syringe (syringe 10) described in Japanese Utility ModelPublication No. Hei 2-15502, a stopper (regulation ring 56) is movablein the longitudinal direction by being rotated relative to a pusher(plunger 22). Upon an operation of pressing the pusher against an outertube (hollow cylinder 2) in the condition where the stopper has beenmoved to a desired position of the pusher, the stopper comes intoabutment on the base end of the outer tube, whereby the movement of thepusher is restricted. Incidentally, the symbols used here are the sameas those described in the publication.

In the syringe described in the publication, however, a means for fixingthe stopper relative to the pusher is not provided, and, therefore, theposition of the stopper relative to the pusher may easily change, makingit difficult to maintain the desired discharge amount of the liquid. Inaddition, since the stopper is moved by rotation relative to the pusher,the operation for moving the stopper is extremely intricate to perform.

On the other hand, in the syringe (syringe 1) described in JapaneseUtility Model Laid-open No. Sho 62-119944, a stopper (stopper 3) ismovable along the longitudinal direction of a pusher (piston 2). Upon anoperation of pressing the pusher against an outer tube (cylinder 4) inthe condition where the stopper has been moved to a desired position ofthe pusher, the stopper comes into abutment on the base end of the outertube, whereby the movement of the pusher is restricted.

In the syringe described in the publication, however, the stopper isprovided with a hole for passing the pusher therethrough, and thestopper is fixed relative to the pusher by the engagement of an engaginggroove 5, formed in the outer circumferential surface of the pusher,with an edge portion of the hole. Therefore, a strong force is requiredfor the operation of moving the stopper relative to the pusher.Incidentally, the symbols used here are the same as those described inthe publication.

Accordingly, it is an object of the present invention to provide asyringe with which an accurate amount of a liquid can be dischargedthrough a simple operation.

DISCLOSURE OF INVENTION

The above object can be attained by the present invention as follows.

Specifically, the above object can be attained by the inventions as setforth in the following paragraphs (1) to (26).

(1) A syringe including: an outer tube, a gasket slidable in the outertube, a pusher inserted through an opening of a base end of the outertube and operable for moving the gasket, a stopper disposed on thepusher to be slidable along the longitudinal direction of the pusher,fixing means for selecting and fixing the position of the stopper on thepusher, and an operating portion provided in the stopper for performinga pressing operation, a traction operation or a pinching operation,wherein the position of the stopper on the pusher can be regulated byreleasing the fixation by the fixing means through an operation at theoperating portion, and the depth of insertion of the pusher into theouter tube is restricted by abutment of the stopper on a portion of theouter tube.

(2) A syringe as set forth in the above paragraph (1), wherein thefixing means is returned to a fixation state by elasticity when theoperation on the operating portion is released.

(3) A syringe as set forth in the above paragraph (1) or (2), whereinthe fixing means includes a rack provided on the pusher and including aplurality of engaging recessed portions or engaging projected portionsprovided at a predetermined interval along the longitudinal direction ofthe pusher, and an engaging portion provided on the stopper to bedisplaceable between a state of being engaged with the rack and a stateof being retracted from the rack, and the engaging portion is normallyengaged with the rack and is retracted from the rack by an operation atthe operating portion.

(4) A syringe as set forth in the above paragraph (3), wherein thefixing means includes a pressing portion operated in conjunction withthe operating portion to be displaced between a first position forpressing the engaging portion to be engaged with the rack and a secondposition for releasing the pressing, and biasing means biasing thepressing portion to bring into the first position, and the fixing meansis normally in such a state that the pressing portion is located in thefirst position and the engaging portion is engaged with the rack to fixthe stopper, the fixing means being so operated that, when the operatingportion is operated, the pressing portion is moved to the secondposition, whereby the engageing portion is retracted from the rack and afixation of the stopper is released, and when the operation on theoperating portion is released, the fixing means is returned into thestate for fixation of the stopper by the biasing force of the biasingmeans.

(5) A syringe as set forth in the above paragraph (3), wherein thefixing means includes biasing means biasing the engaging portion todisplace from a state of being retracted from the rack to a state ofbeing engaged with the rack, the fixing means is normally in such astate that the engaging portion is engaged with the rack to fix thestopper, and the fixing means is so operated that, when the operatingportion is operated, the engaging portion is retracted from the rack torelease a fixation of the stopper, and when the operation on theoperating portion is released, the fixing means is returned into thestate for fixation of the stopper by the biasing force of the biasingmeans.

(6) A syringe as set forth in any of the above paragraphs (3) to (5),wherein the pusher includes a main body portion in such a shape thatplate pieces are intersected in a cross form, and the rack is formed ina portion of the plate pieces.

(7) A syringe as set forth in any of the above paragraphs (3) to (6),wherein a pair of the racks are provided.

(8) A syringe as set forth in any of the above paragraphs (1) to (7),wherein the pusher includes a rail portion, and the stopper includes aslide portion slid along the rail portion, and the stopper is slid alongthe longitudinal direction of the pusher by guiding of the slide portionon the rail.

(9) A syringe as set forth in any of the above paragraphs (1) to (8),wherein the maximum width of the stopper is smaller than the maximumwidth of the pusher.

(10) A syringe as set forth in any of the above paragraphs (1) to (9),wherein the operating portion is operated by being pressed by a finger.

(11) A syringe as set forth in any of the above paragraphs (1) to (10),wherein the operating portion is operated by being pinched betweenfingers.

(12) A syringe including: an outer tube, a gasket slidable in the outertube, a pusher inserted through an opening of a base end of the outertube and operable for moving the gasket, a stopper provided on thepusher so that the stopper can be slid along the longitudinal directionof the pusher and the position of the stopper on the pusher can beregulated to a desired position, and an operating member provided to bedisplaceable relative to the stopper, the operating member performing anoperation of fixing the stopper relative to the pusher by pressing aportion of the stopper against the pusher, wherein the depth ofinsertion of the pusher into the outer tube is restricted by abutment ofthe stopper on a portion of the outer tube.

(13) A syringe as set forth in the above paragraph (12), wherein eitherone or both of abutment surfaces of the stopper and the pusher areformed as rough surfaces or are formed of a material having a highfrictional resistance.

(14) A syringe as set forth in the above paragraph (13), wherein thematerial having a high frictional resistance is an elastic material.

(15) A syringe as set forth in the above paragraph (13) or (14), whereinthe pusher is provided with a pair of the abutment surfacessubstantially parallel to each other.

(16) A syringe as set forth in the above paragraph (15), wherein theabutment surfaces of the pusher are opposed to each other.

(17) A syringe as set forth in the above paragraph (16), wherein theabutment surfaces of the pusher are on a same plane.

(18) A syringe as set forth in any of the above paragraphs (12) to (17),wherein the stopper includes a stopper main body, and a brake portionpressed against the pusher by an operation of the operating member.

(19) A syringe as set forth in the above paragraph (18), wherein thepressing of the brake portion against the pusher is performed byclamping of the brake portion between a portion of the operating memberand the pusher.

(20) A syringe as set forth in the above paragraph (18), wherein thepressing of the brake portion against the pusher is performed by fittinga portion of the operating member between the stopper main body and thepusher so as to move the stopper main body in the direction for spacingaway from the pusher.

(21) A syringe as set forth in any of the above paragraphs (18) to (20),wherein the operating member is turnable relative to the stopper mainbody.

(22) A syringe as set forth in any of the above paragraphs (18) to (21),wherein the operating member is slidable relative to the stopper mainbody.

(23) A syringe as set forth in any of the above paragraphs (12) to (22),wherein the pusher includes a rail portion for guiding the stopper, anda portion of the stopper is pressed against the rail portion.

(24) A syringe as set forth in any of the above paragraphs (1) to (23),wherein the pusher is provided thereon with graduations for indicatingthe position of the stopper corresponding to the amount of a liquiddischarged.

(25) A syringe as set forth in the above paragraph (24), wherein thepusher includes positioning means for positioning the stopper at theposition of 0 (zero) of the graduations.

(26) A syringe as set forth in any of the above paragraphs (1) to (25),wherein a chemical is preliminarily contained in a space surrounded bythe outer tube and the gasket.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a partly vertical sectional view of a first embodiment of thesyringe according to the present invention.

FIG. 2 is a perspective view (in an exploded state) of a stopper in thesyringe shown in FIG. 1.

FIG. 3 is a sectional view along line X-X of FIG. 2.

FIG. 4 is a sectional view along line Y-Y of FIG. 2.

FIG. 5 is a partly sectional perspective view (in a state the stopperbeing fixed) showing a main body portion of a pusher and a stopper inthe syringe shown in FIG. 1.

FIG. 6 is a partly sectional perspective view (in a state a fixationbeing released) showing the main body portion of the pusher and thestopper in the syringe shown in FIG. 1.

FIG. 7 is a perspective view of a main body portion of a pusher and astopper in a second embodiment of the syringe according to the presentinvention.

FIG. 8 is a partly sectional perspective view (in a state the stopperbeing fixed) showing a main body portion of a pusher and a stopper in athird embodiment of the syringe according to the present invention.

FIG. 9 is a partly sectional perspective view (in a state a fixationbeing released) showing the main body portion of the pusher and thestopper in the third embodiment of the syringe according to the presentinvention.

FIG. 10 is a partly sectional perspective view (in a state the stopperbeing fixed) showing a pusher and a stopper in a fourth embodiment ofthe syringe according to the present invention.

FIG. 11 is a partly sectional perspective view (in a state a fixationbeing released) showing the pusher and the stopper in the fourthembodiment of the syringe according to the present invention.

FIG. 12 is an exploded perspective view of a pusher portion in a fifthembodiment of the syringe according to the present invention.

FIG. 13 shows perspective views illustrating the operating conditions ofa stopper attached to the pusher portion shown in FIG. 12.

FIG. 14 is a plan view showing a main body portion of a pusher and astopper in a sixth embodiment of the syringe according to the presentinvention.

FIG. 15 shows partly sectional side views illustrating the operatingconditions of a stopper attached to the pusher portion shown in FIG. 14.

FIG. 16 shows sectional views along line A-A of FIG. 15.

FIG. 17 shows sectional views along line B-B of FIG. 15.

FIG. 18 is an exploded perspective view of a pusher portion in a seventhembodiment of the syringe according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, the present invention will be described in detail below.

The syringe according to the present invention will be described indetail below, based on preferred embodiments shown in the drawings.

FIRST EMBODIMENT

FIG. 1 is a partly vertical sectional view showing a first embodiment ofthe syringe according to the present invention, FIG. 2 is a perspectiveview (in an exploded state) of a stopper in the syringe shown in FIG. 1,FIG. 3 is a sectional view along line X-X of FIG. 2, FIG. 4 is asectional view along line Y-Y of FIG. 2, and FIGS. 5 and 6 are partlysectional perspective views showing a main body portion of a pusher anda stopper in the syringe shown in FIG. 1. Incidentally, for convenienceof description, the side of an outer tube of the syringe in FIG. 1 willbe referred to as “the tip end”, and the side of the pusher as “the baseend”; the side of a second member of the stopper in FIG. 2 will bereferred to as “upper”, and the side of a first member as “lower”; theside of projected portions provided on a leaf spring of the first memberin FIGS. 3 and 4 will be referred to as “upper”, and the opposite sideas “lower”; and the side of the stopper in FIGS. 5 and 6 will bereferred to as “upper”, and the side of the main body portion of thepusher as “lower”.

The syringe 1 in this embodiment shown in FIG. 1 is a pre-filled syringewith the inside of the syringe being pre-filled with a chemical, andincludes an outer tube (syringe outer tube) 2, a gasket 3 slidable inthe outer tube 2, a pusher (plunger rod) 4 operable for moving thegasket 3, and a stopper 5 disposed to be slidable along the longitudinaldirection of the pusher 4. The gasket 3 is connected to the tip end ofthe pusher 4. Now, the configurations of the individual portions will bedescribed below.

The outer tube 2 is composed of a bottomed tubular member having abottom portion 21 on the tip end side, and the bottom portion 21 isintegrally provided at its central portion with a tubulardiameter-reduced portion 22 which is reduced in diameter as comparedwith a body portion of the outer tube 2. The diameter-reduced portion 22opens at its tip end portion, and, for example, a hub, a connector orthe like (not shown) of a needle pipe is fitted in the opening and isused.

A base end portion of the diameter-reduced portion 22 may be providedwith a male screw (lure lock screw) along the outer circumferencethereof.

A film 24 formed of an elastic material, as a sealing member, isattached to the tip end of the diameter-reduced portion 22 so as tocover the opening at the tip end of the diameter-reduced portion 22,thereby sealing gas-tightly a lumen 23 of the diameter-reduced portion22.

In addition, a bottomed tubular cap 29 having a bottom portion on thetip end side is fitted over and fixed to the outside surface of thediameter-reduced portion 22. The cap 29 is provided with an opening 291at its tip end, and an outer circumferential portion of the film 24 isclamped between an edge portion of the opening 291 and the tip end faceof the diameter-reduced portion 22, whereby the film 24 is fixed in agas-tight (liquid-tight) manner.

Incidentally, the diameter-reduced portion 22, the film 24 and the cap29 may be adhered to each other with an adhesive or fused to each other.

The film 24 can be punctured by a needle body such as a double endedneedle. In this case, the form of the film 24 is not limited to thefilm-like form, as long as the film 24 can be punctured by a needlebody; for example, the film 24 may be a block-form body (plug body).

As a material for constituting the film 24, for example, those materialswhich will be mentioned as constituent material of the gasket 3 latercan be used.

Incidentally, the sealing member for sealing the tip end of thediameter-reduced portion 22 is not limited to the configuration shown inthe figure; for example, the sealing member may be a thin film or thelike (not shown).

Besides, the base end of the outer tube 2 is integrally provided with aplate-like flange 25 along the outer circumference thereof. At the timeof, for example, an operation for moving the pusher 4 relative to theouter tube 2, the operation can be conducted with a finger put on theflange 25.

The material for constituting the outer tube 2 is particularly limited.Examples of the constituent material usable include various resins suchas polyvinyl chloride, polyethylene, polypropylene, cyclic polyolefins,polystyrene, poly-(4-methylpentene-1), polycarbonate, acrylic resins,acrylonitrile-butadiene-styrene compolymer, polyesters such aspolyethylene terephthalate and polyethylene naphthalate,butadiene-styrene copolymer, and polyamides (e.g., nylon 6, nylon 6,6,nylon 6,10, nylon 12). In terms of little moisture loss, the resins suchas polypropylene, cyclic polyolefins, polyesters, andpoly-(4-methylpentene-1), of the above examples are preferable.

Incidentally, the constituent material of the outer tube 2 preferably issubstantially transparent, for securing visibility of the insidethereof.

A chemical 100 is contained liquid-tightly in the space surrounded bythe outer tube 2 and the gasket 3. The form of the chemical 100 may bearbitrary; for example, the chemical 100 may be in a solid form(inclusive of powder form and granular form), a liquid form or the like.In this embodiment, a chemical in a liquid form will be described as arepresentative.

Examples of the chemical 100 include a variety of chemicals such asantitumor agents, anesthetics, stimulants, narcotics, carbohydrateinjections such as glucose, electrolyte correction injections such assodium chloride and potassium lactate, vitamin agents, vaccines,antibiotic injections, contrast media, steroid agents, proteaseinhibitors, lipid emulsions, etc., and also include distilled water,disinfectants, fluid foods, alcohols, etc.

The outer tube 2 is provided with graduations 27 on the outercircumferential surface thereof. This makes it possible to grasp theamount of the liquid contained in the syringe 1. In the configurationshown in the figure, the graduations 27 range from 0 to 5 mL.

The gasket 3 formed of an elastic material and slidable in thelongitudinal direction of the outer tube 2 is contained in the outertube 2.

The gasket 3 is provided at its outer circumferential portion with aplurality of annular projected portions 31, 32 and 33 over the entirecircumference. The projected portions 31, 32 and 33 keep close contactwith an inner circumferential surface 26 of the outer tube 2 duringsliding, whereby the liquid-tightness can be securely maintained, andenhancement of slidability can be contrived.

In this embodiment, three projected portions 31, 32 and 33 are providedalong the longitudinal direction of the syringe 1. Specifically, theprojected portions 31, 32 and 33 are provided at a base end portion, anintermediate portion and a tip end portion of the gasket 3,respectively. In addition, a tip end surface 36 of the gasket 3 is atapered surface whose diameter is gradually reduced toward the tip end.

Incidentally, in the present invention, the positions, the number, thecross-sectional shape and the like of the projected portions 31, 32 and33 are not limited to the above-mentioned.

In addition, the gasket 3 is provided with a hollow portion 34 openingat the base end face thereof. A head portion 43 of the pusher 4 whichwill be described later is inserted (screw-engaged) into the hollowportion 34. The hollow portion 34 is provided with a female screw 341 atthe inside surface thereof.

The material for constituting the gasket 3 is not particularly limited.Examples of the constituent material usable include elastic materialssuch as various rubber materials, e.g., natural rubber, butyl rubber,isoprene rubber, butadiene rubber, styrene-butadiene rubber, siliconerubber, etc., various thermoplastic elastomers based on polyurethane,polyester, polyamide, polyolefin, styrene or the like, and mixturesthereof.

Incidentally, it suffices that at least an outer circumferential portionof the gasket 3 is constituted of the above-mentioned elastic material.For example, there may be adopted a configuration in which the gasket 3includes a core portion (not shown) constituted of a resin material andthe elastic material is disposed to cover the outer circumference of thecore portion. In this case, the female screw 341 is provided at the coreportion.

To such a gasket 3 is connected (attached) the pusher 4 for movablyoperating the gasket 3 in the outer tube 2 in the longitudinaldirection.

The pusher 4 includes a main body portion 40 in such a shape that platepieces 44 and 46 are intersected in a cross form, and the main bodyportion 40 is provided at its base end with a flange-formed fingerreceiving portion 401. With the finger receiving portion 401 pressed bya finger or the like, the pusher 4 is moved in the tip end direction.

On the tip end side of the main body portion 40, a first flange 41formed in a sword-guard like shape and a second flange 42 located on thebase end side relative to the first flange 41 are provided integrallywith the main body portion 40. The first flange 41 and the second flange42 are disposed substantially in parallel to each other, at apredetermined interval of about 3 to 50 mm, for example.

Further, on the tip end side relative to the first flange 41, the pusher4 is provided with a head portion (connection portion) 43 inserted inthe hollow portion 34 of the gasket 3 and connected to the gasket 3.

The head portion 43 is provided at its outer circumference with a malescrew 431 which is screw-engageable with the female screw 341 formed atthe inside surface of the hollow portion 34. By screw engagement of themale screw 431 and the female screw 341 with each other, the gasket 3and the pusher 4 are connected to each other. In such a connectedcondition, the tip end face of the first flange 41 is in contact orclose contact with the base end face of the gasket 3.

Incidentally, in the present invention, the connection structure betweenthe gasket 3 and the pusher 4 is not limited to the screw engagement;for example, attachment such as adhesion, fusing, etc., fitting, loosefitting and the like may also be adopted for the connection.

The material for constituting the pusher 4 is not particularly limited;for example, the same materials as those mentioned above as theconstituent material of the outer tube 2 can be used.

In addition to the above-described configuration, the syringe 1according to the present invention includes a stopper (insertion depthrestrictive member) 5 disposed to be movable along the longitudinaldirection of the pusher 4, and a fixing means for selecting (regulating)and fixing the position of the stopper 4 on the pusher 4. As shown inFIG. 1, the stopper 5 is disposed on the main body 40 on the base endside relative to the second flange 42.

In the syringe 1, at the time of discharging the chemical 100 bypressing the pusher 4 to move in the direction of the tip end, a tip endsurface 66 of the stopper 5 abuts on a base end portion (base end face)28 of the outer tube 2, whereby the depth of insertion of the pusher 4into the outer tube 2 is restricted. This makes it possible to dischargean accurate amount of the chemical 100. Now, the configuration of thestopper 5 and the fixing means will be described in detail below.

As shown in FIG. 2, the stopper 5 is composed of a first member 6, and asecond member 7. The first member 6 and the second member 7 are eachsubstantially symmetric on the left and right sides in FIG. 2.

The first member 6 includes a roughly box-like casing 61 opened on thelower side in FIG. 2. As shown in FIG. 4, the casing 61 is provided, atits left and right lower end portions in the figure, with projectedslide portions 62 a and 62 b roughly angular U-shaped in section. Thefirst member 6 is slidable (movable) along the longitudinal direction ofthe pusher 4, with the slide portions 62 a and 62 being slid on railportions 441 and 451 provided on the pusher 4.

In this embodiment, as shown in FIG. 1, edge portions of the twoparallel plate pieces 44 and 45, of the four plate pieces 44, 45, 46 and46 intersecting in a cross form to constitute the main body portion 40of the pusher 4, constitute the rail portions 441 and 451, respectively.As shown in FIG. 5, the rail portions 441 and 451 are insertedrespectively into the inside of the slide portions 62 a and 62 b, andthe inside surfaces of the slide portions 62 a and 62 b are slid alongthe rail portions 441 and 451, whereby the first member 6 is guidedalong the longitudinal direction of the pusher 4.

As shown in FIG. 4, the lower surfaces of the slide portions 62 a and 62b, on the inside, are inclined tapered surfaces 621 a and 621 b,respectively. This ensures that, at the time of mounting the firstmember 6 to the pusher 4 in the process of assembling the syringe 1, therail portions 441 and 451 are slid on the tapered surfaces 621 a and 621b, whereby the slide portions 62 a and 62 b are elastically deformed inthe manner of being pressed wider to the outside, permitting easymounting.

As shown in FIGS. 2 and 4, a tip end wall 614 and a base end wall 615 ofthe casing 61 are respectively provided in grooves 611 and 612 incentral portions thereof. In the condition where the first member 6 ismounted to the pusher 4, the plate piece 46 orthogonal to the platepieces 44 and 45 of the main body portion 40 is inserted in the grooves611 and 612.

As shown in FIGS. 1 and 5, side surfaces of the plate piece 46 areprovided with racks 47 a and 47 b including a plurality of engagingrecessed portions 471 formed at a predetermined interval along thelongitudinal direction of the pusher 4. Engaging portions 63 a and 63 bprovided in the first member 6 are engaged with the racks 47 a and 47 b,whereby the stopper 5 is fixed to the pusher 4.

In this embodiment, a pair of the racks 47 a, 47 b and a pair ofengaging portions 63 a, 63 b are provided. This enables securer fixationof the stopper 5 to the pusher 4. The pair of racks 47 a and 47 b areprovided on both side surfaces of the plate piece 46, respectively.

The interval (pitch) of the engaging recessed portions 471 in the racks47 a, 47 b is not particularly limited, and is appropriately setaccording to the volume of the syringe 1 or the like. For example, theinterval (pitch) can be set to correspond to one of increments (ordecrements) of 0.1 mL, 0.2 mL, 0.5 mL, 1 mL, 5 mL, 10 mL and the like ofthe amount of the liquid discharged from the syringe 1. In theconfiguration shown in the figures, the interval of the engagingrecessed portions 471 corresponds to a discharge amount increment (ordecrement) of 0.1 mL. In such a case, the pitch of the engaging recessedportions 471 is determined in relation to the diameter of the outer tube2 of the syringe 1. In view of enabling minute regulation, the pitch ispreferably not more than 4 mm, and more preferably not more than 2 mm.

In the configuration shown in the figures, the engaging recessedportions 471 are composed of roughly V-shaped grooves. This enables thestopper 5 to be fixed accurately, without chattering. In addition, theplurality of engaging recessed portions 471 are formed adjacent to eachother, so that the racks 47 a and 47 b are serrate.

Incidentally, in the present invention, the shape of the engagingrecessed portions 471 is not limited to that shown in the figures. Forexample, the engaging recessed portions 471 may be composed of U-shaped,roughly angular U-shape or semicircular grooves, or holes or the like.Besides, the engaging recessed portions 471 are not limited to thosewhich are formed adjacent to each other as shown in the figures, and maybe intermittently formed at a predetermined interval.

As shown in FIG. 5, a pair of engaging portions 63 a and 63 b capable ofengagement with the racks 47 a and 47 b are provided in the inside ofthe casing 61.

As shown in FIG. 4, the engaging portions 63 a and 63 b are formed inthe shape of arms projecting from an upper wall 613 (see FIG. 2) of thecasing 61 toward the inside of the casing 61.

As shown in FIG. 5, the plate piece 46 is located between the engagingportions 63 a and 63 b. On the lower end side of the engaging portions63 a and 63 b, projections 631 a and 631 b formed in a wedge shape (Vshape) corresponding substantially to the shape of the engaging recessedportions 471 are provided to project toward the inside, and theprojections 631 a and 631 b are respectively inserted into the engagingrecessed portions 471 of the racks 47 a and 47 b, whereby both of themare engaged with each other.

The engaging portions 63 a and 63 b are provided with roughlyhemispherical projected portions 632 a and 632 b on the opposite side(outside) of the projections 631 a and 631 b.

In addition, as shown in FIG. 2, the upper wall 613 is provided withholes 64 a and 64 b on the outside of the locations of the engagingportions 63 a and 63 b, respectively.

Besides, as shown in FIG. 3, the upper wall 613 is integrally providedwith a cantilever leaf spring (biasing means) 65 at a central portionthereof. The leaf spring 65 has a curved shape, and is provided at itscentral portion with a roughly hemispherical projected portion 651projecting to the outside (upper side). When the leaf spring 65 is in anatural state, the projected portion 651 is in the state of protrudingfrom the upper wall 613; when the leaf spring 65 is deflected downwards,the projected portion 651 sinks into the inside of the casing 61.

As shown in FIG. 2, the second member 7 includes a roughly plate-likeoperating portion 71, a pair of pressing portions 72 a and 72 bprojecting in an arm shape from the lower surface of the operatingportion 71, and a rib 73 formed on the upper surface of the operatingportion 71.

The operating portion 71 is a portion to be depressed by a finger, i.e.,it functions as a pushbutton. The rib 73 displays an anti-slippingeffect at the time of depressing the operating portion 71 by a finger.The pressing portions 72 a and 72 b display the function of respectivelypressing the engaging portions 63 a and 63 b to the inside.

As shown in FIG. 5, the second member 7 is mounted to the first member 6in the condition where the pressing portions 72 a and 72 b are insertedrespectively in the holes 64 a and 64 b (see FIG. 2). In this condition,claws 723 a and 723 b formed on the pressing portions 72 a and 72 b areengaged with claws 641 a and 641 b formed on the inside surfaces of theholes 64 a and 64 b, whereby the second member 7 is prevented fromslipping off from the first member 6 (see FIGS. 2 and 4).

As shown in FIGS. 2 and 5, projected portions 721 a and 721 b projectingto the inside are provided respectively at lower end portions of thepressing portions 72 a and 72 b. In addition, the projected portions 721a and 721 b are provided with inclined tapered surfaces 722 a and 722 bon the upper side.

The second member 7 is normally in the condition where the operatingportion 71 is lifted (spaced) from the upper wall 613 by the biasingforce of the leaf spring 65, as shown in FIG. 5. When the operatingportion 71 is depressed by a finger, the second member 7 is displaceddownwards against the biasing force of the leaf spring 65, and the lowersurface of the operating portion 71 comes into contact with the upperwall 613, as shown in FIG. 6. In conjunction with such operations at theoperating portion 71, the pressing portions 72 a and 72 b are eachdisplaced between a first position shown in FIG. 5 and a second positionshown in FIG. 6 which is deviated downwards from the first position.

As shown in FIG. 5, when the pressing portions 72 a and 72 b are intheir first positions, i.e., in the condition where the operatingportion 71 is not depressed, the projected portions 721 a and 721 b arelocated at the same location (height) as the projected portions 632 aand 632 b, and are pressing the projected portions 632 a and 632 binwards. This results in that the engaging portions 63 a and 63 b aredisplaced inwards, and the projections 631 a and 631 b are inserted intothe engaging recessed portions 471 of the racks 47 a and 47 b,respectively. Thus, in the condition shown in FIG. 5, the engagingportions 63 a and 63 b are in engagement with the racks 47 a and 47 b,whereby the stopper 5 is fixed to the pusher 4.

As shown in FIG. 6, when the pressing portions 72 a and 72 b are intheir second positions, i.e., in the condition where the operatingportion 71 is depressed, the projected portions 721 a and 721 b arelocated on the lower side relative to the projected portions 632 a and632 b, so that the pressing on the projected portions 632 a and 632 b isreleased (canceled). This results in that the engaging portions 63 a and63 b are displaced outwards by their own elasticity, and the projections631 a and 631 b are retracted from the engaging recessed portions 471 ofthe racks 47 a and 47 b. Thus, in the condition shown in FIG. 6,fixation of the stopper 5 is released (canceled), and the stopper 5 canbe slid (moved) relative to the pusher 4.

When the depression on the operating portion 71 is released startingfrom the condition of FIG. 6, the second member 7 is displaced upwardsby the biasing force of the leaf spring 65, and the pressing portions 72a and 72 b are returned to their first positions, resulting in thefixation condition shown in FIG. 5. In this instance, the projectedportions 632 a and 632 b can be smoothly returned to the condition ofFIG. 5 by being pressed by the projected portions 721 a and 721 b whilesliding on the tapered surfaces 722 a and 722 b, respectively.Particularly in the configuration shown in the figures, thehemispherical shape of the projected portions 632 a and 632 b reducesthe friction between the projected portions 632 a, 632 b and the taperedsurfaces 722 a, 722 b, so that the returning action occurs more smoothlyand securely.

As has been described above, in the syringe 1, the stopper 5 is slid onthe pusher 4 by depressing the operating portion 71 with a finger,whereby the position of the stopper 5 can be regulated. In addition,when the finger is detached from the operating portion 71 to release(remove) the depression, the stopper 5 is fixed in situ relative to thepusher 4. With the position of the stopper 5 on the pusher 4 thusregulated, the insertion depth of the pusher 4 insertable into the outertube 2 can be changed, so that the amount of the chemical 100 dischargedcan be set to a desired amount.

Namely, in this embodiment, the racks 47 a, 47 b, the engaging portions63 a, 63 b, the leaf spring 65 and the pressing portions 72 a, 72 bconstitute the fixing means for selecting and fixing the position of thestopper 5 on the pusher 4.

As shown in FIG. 1, the pusher 4 (leaf spring 44) is provided withgraduations 48 corresponding to the amount of the liquid discharged fromthe syringe 1. As will be described later, by pushing in the pusher 4under the condition where the position of the tip end face 66 of thestopper 5 (first member 6) is matched to the graduations 48, it ispossible to discharge a desired amount of the chemical 100.

The graduations 48 correspond to the graduations 27 provided on theouter tube 2, and, in the configuration shown, the graduations 48 areformed at positions corresponding to discharge liquid amounts of 0 to 5mL.

In addition, the pusher 4 is provided with a positioning means forpositioning the stopper 5 to 0 (zero) of the graduations 48. In thisembodiment, the positioning means is composed of the second flange 42.Specifically, a base end face 421 of the second flange 42 is at aposition corresponding to 0 (zero) of the graduations 48. This ensuresthat positioning of the stopper 5 to 0 (zero) of the graduations 48(zero point setting) can be easily achieved by moving the stopper 5 inthe tip end direction until the tip end face 66 abuts on the base endface 421 of the flange 42. With the zero point setting, it is possibleto set the amount of the chemical 100 discharged to a more accurateamount, as will be described later.

Incidentally, the positioning means is not limited to such aconfiguration as the flange 42, as long as the positioning meansprevents the stopper 5 from moving further in the tip end direction. Forexample, a step formed at an edge portion of the plate piece 46 or thelike may also be adopted as the positioning means.

The material for constituting the stopper 5 is not particularly limited.Examples of the constituent material of the outer tube 2 which areusable include not only various synthetic resin materials like thosementioned above as the constituent material of the outer tube 2 but alsovarious metallic materials such as stainless steels, aluminum oraluminum alloys, titanium or titanium alloys, copper or copper alloys,etc.

Incidentally, the fixing means for the stopper 5 may be one in whichengaging portions constituted of recessed portions provided in thestopper are engaged with engaging projected portions formed in theracks. In such a case, the shape of the engaging projected portions ofthe racks may be arbitrary; for example, a V shape, a U shape, a roughlyangular U shape, a semicircular shape and the like may be adopted.

In addition, the biasing means for biasing the second member 7 (pressingportions 72 a, 72 b) is not limited to the leaf spring 65, and may beany one; for example, the biasing means may be composed of a separatemember such as a coil spring.

Incidentally, while a pair of the racks 47 a, 47 b and a pair of theengaging portions 63 a, 63 b are provided in this embodiment, one rackand one engaging portion may be provided in the present invention;further, three or more racks and three or more engaging portions may beprovided in the present invention.

Next, one example of the method of using the syringe 1 will bedescribed. The method described below pertains to an exemplary case inwhich a double ended needled holder (not shown) including a bottomedtubular holder main body and a double ended needle (needle pipe) havingsharp needle ends at both ends thereof is connected to the syringe 1,and the chemical 100 is mixedly injected into a bottle-shaped orbag-shaped injection vessel (not shown).

[1A] First, the stopper 5 is positioned to 0 (zero) of the graduations48 (zero point setting). Specifically, while pressing the operatingportion 71 with a finger, the stopper 5 is moved to a maximum degreetoward the side of the tip end of the pusher 4, bringing the tip endface 66 of the stopper 5 into contact with the base end face 421 of thesecond flange 42. As has been described above, when the finger isdetached from the operating portion 71, the stopper 5 is fixed in siteon the pusher 4.

[2A] Next, deaeration of the outer tube 2 is conducted as follows. Asshown in FIG. 1, the syringe 1 is charged with the chemical 100 in anamount slightly larger than a prescribed amount (5 mL, in theconfiguration shown in the figures). The holder main body of the doubleended needled holder is fitted over the cap 29 of the syringe 1. Thisresults in that one of the needle ends of the double ended needlepierces through the film 24, entering into the lumen 23 of thediameter-reduced portion 22. After the double ended needled holder isthus fitted, a finger is put on the finger receiving portion 401 of thepusher 4, and the pusher 4 is moved in the tip end direction relative tothe outer tube 2 until the tip end face 66 of the stopper 5 abuts on thebase end portion 28 of the outer tube 2. By this operation, the gasket 3connected to the pusher 4 is slid in the outer tube 2 in the tip enddirection, and a surplus amount of the chemical 100 and air in the outertube 2 are discharged through the lumen 23 of the diameter-reducedportion 22 and the double ended needle.

Upon this operation, the amount of the chemical 100 in the outer tube 2is equal to the prescribed amount. In other words, under this condition,the outer circumferential portion tip end (projected portion 33) of thegasket 3 is located at the position, corresponding to the prescribedamount (5 mL, in the configuration shown in the figures), in thegraduations 27 on the outer tube 2.

[3A] Subsequently, the other end of the double ended needle of thedouble ended needled holder is caused to pierce through a plug bodysealing a mouth portion of the injection vessel. In this condition, theinside of the outer tube 2 and the interior space of the injectionvessel are communicated with each other through the double ended needle.

[4A] Next, while pressing the operating portion 71 with a finger, thestopper 5 is slid on the pusher 4 so as to position the tip end face 66of the stopper 5 to a position, corresponding to the desired dischargeamount, on the graduations 48. In the configuration shown in thefigures, for example, where 1 mL of the chemical 100 is to bedischarged, the tip end face 66 is positioned to “1” on the graduations48. Where 3 mL of the chemical 100 is to be discharged, the tip end face66 is positioned to “3” on the graduations 48.

[5A] Subsequently, a finger is put on the finger receiving portion 401,the pusher 4 is pushed in the tip end direction, and the pusher 4 ismoved in the tip end direction relative to the outer tube 2 until thetip end face 66 of the stopper 5 abuts on the base end portion 28 of theouter tube 2. By this operation, the gasket 3 connected to the pusher 4is slid in the outer tube 2 in the tip end direction, and the set amountof the chemical 100 is discharged from the outer tube 2 through thelumen 23 of the diameter-reduced portion 22 and the double ended needle,to be blended into the injection present in the injection vessel.

Thus, in the present invention, the depth of insertion of the pusher 4into the outer tube 2 is restricted by the abutment of the stopper 5 onthe outer tube 2; therefore, the pusher 4 is prevented from being pushedexcessively or insufficiently, and the set amount of the chemical 100can be discharged accurately. Therefore, a mistake such that the amountof the chemical 100 discharged is excessive or insufficient can beprevented from occurring.

In addition, in the syringe 1, the fixation of the stopper 5 can bereleased (canceled) and the position of the stopper 5 on the pusher 4can be regulated, in a one-stroke operation of simply pressing theoperating portion 71 with a finger. This ensures that the operation ofsetting the amount of the chemical 100 to be discharged can be performedextremely easily and swiftly.

Besides, when the depression on the operating portion 71 is released,the stopper 5 is automatically returned to the fixed state, so that theposition of the stopper 5 once set is prevented from being deviated withthe result of an error in the set discharge amount.

In addition, in the operation of discharging the chemical 100, theabove-mentioned effect can be attained by the simple operation of onlymoving the pusher 4 in the tip end direction until the stopper 5 abutson the outer tube 2, so that the operation of the pusher 4 does not needa subtle regulation of force, and the operation is easy to perform.

Incidentally, other than the above-described method of using the syringe1, a method of using the syringe 1 in which a surplus amount of thechemical 100 is preliminarily discarded can also be adopted.

[1B] The case of using only 3 mL of the prescribed amount of 5 mL, inthe configuration shown in the figures, will be described as an example.First, the tip end face 66 of the stopper 5 is adjusted to a position,corresponding to the surplus amount of the chemical 100, on thegraduations 48. In this case, since the amount to be used is 3 mLagainst the prescribed amount of 5 mL and the surplus amount istherefore 2 mL, the tip end face 66 is adjusted to “2” on thegraduations 48.

[2B] Next, the double ended needled holder is mounted to the cap 29 ofthe syringe 1 in the same manner as above, then a finger is put on thefinger receiving portion 401 of the pusher 4, and the pusher 4 is movedin the tip end direction relative to the outer tube 2 until the tip endface 66 of the stopper 5 comes into contact with the base end portion 28of the outer tube 2. By this operation, the gasket 3 connected to thepusher 4 is slid in the outer tube 2 in the tip end direction, and thesurplus amount of the chemical 100 and air in the outer tube 2 aredischarged through the lumen 23 of the diameter-reduced portion 22 andthe double ended needle. As a result of the operation, deaeration isachieved, and 3 mL of the chemical 100 is left in the outer tube 2. Inother words, under this condition, the outer circumferential portion tipend (projected portion 33) of the gasket 3 is located at “3” of thegraduations 27 on the outer tube 2.

[3B] Subsequently, in the same manner as above, the other end of thedouble ended needle of the double ended needled holder is caused topierce through the plug body sealing the mouth portion of an injectionvessel, whereby the inside of the outer tube 2 and the interior space ofthe injection vessel are communicated with each other.

[4B] Next, while pressing the operating portion 71 with a finger, thestopper 5 is slid on the pusher 4, to a base end portion (on the baseend side relative to “5” of the graduations 48, in the configurationshown in the figures) of the pusher 4.

[5B] Subsequently, a finger is put on the finger receiving portion 401,the pusher 4 is pressed, and the pusher 4 is moved in the tip enddirection until the tip end face 36 of the gasket 3 comes into contactwith (or into proximity to) the bottom portion 21 of the outer tube 2,thereby discharging substantially completely the chemical 100 remainingin the outer tube 2. By this operation, the desired amount (3 mL) of thechemical 100 can be blended into the injection in the injection vessel.

Incidentally, while the syringe 1 pre-filled with the liquid chemical100 has been described in this embodiment, the chemical 100 in thepresent invention may be solid. In this case, the pusher 4 is pulled inthe base end direction to suck in a liquid through the tip end openingof the diameter-reduced portion 22 into the inside of the outer tube 2,thereby dissolving the chemical 100 in the liquid, before use. Inaddition, the present invention is applicable not only to a pre-filledsyringe such as the syringe 1 but also to an ordinary syringe in which achemical or the like is not sealed.

Besides, while the operating portion 71 has been to be pressed with afinger in this embodiment, an operating portion which is subjected to atraction operation (pulling operation) or a nipping operation (pinchingoperation) with fingers so as to release the fixation of the stopper 5may also be adopted in the present invention.

In addition, naturally, the method of using the syringe 1 is not limitedto the one in which the double ended needled holder as above-describedis used, but may be one in which, for example, a hub, connectors, tubesor the like (not shown) of the needle pipe is fitted over or mounted tothe diameter-reduced portion 22.

SECOND EMBODIMENT

FIG. 7 is a perspective view of a main body portion of a pusher and astopper in a second embodiment of the syringe according to the presentinvention.

The second embodiment of the syringe according to the present inventionwill be described below referring to the drawing. In the following,description will be centered on the differences from the above-describedembodiment, and description of the same items as above will be omitted.

A pusher 4A in this embodiment is one for use in a syringe which islarger in size (capacity) than the syringe 1 in the first embodiment.Namely, the pusher 4A is larger than the pusher 4 in the firstembodiment.

A main body portion 40A of the pusher 4A has a shape such that platepieces are intersected in a cross form. The main body portion 40A isprovided with a stopper 5 the same with or similar to theabove-mentioned. The width (maximum width) of the stopper 5 is smallerthan the width (maximum width) of the main body portion 40A.

From both side surfaces of one plate piece 46A of the four plate piecesconstituting the main body 40A, plate pieces 44A and 45A are projected.Namely, the plate pieces 44A and 45A are intersected with the platepiece 46A at right angles. Edge portions of the plate pieces 44A and 45Aconstitute rail portions 441 and 451 on which the stopper 5 is slid.

The plate piece 46A, located on the upper side relative to the platepieces 44A and 45A in FIG. 7, is provided with racks 47 a and 47 b onboth side surfaces thereof.

Thus, in this embodiment, the stopper 5 having a maximum width smallerthan the maximum width of the main body portion 40A (pusher 4A) can bedisposed and used. Therefore, for example, the stopper 5 having the samesize and configuration as those in the first embodiment can be disposedand used for the pusher 4A larger in size than that in the firstembodiment. Accordingly, in the case of applying the present inventionto a large-sized syringe, a stopper 5 for a small-sized syringe can beused in common, so that it is unnecessary to design and produce alarge-sized stopper and, therefore, to contrive a reduction inproduction cost. In addition, it is possible to contrive a reduction inweight of the syringe, as compared with the case of disposing alarge-sized stopper; therefore, it is possible to preclude bad effectsof an increase in weight, such as worsening of operationality.

THIRD EMBODIMENT

FIGS. 8 and 9 are partly sectional perspective views of a main bodyportion of a pusher and a stopper in a third embodiment of the syringeaccording to the present invention. Incidentally, for convenience ofdescription, the side of the stopper in FIGS. 8 and 9 will be referredto as “upper”, and the side of the main body portion of the pusher as“lower”.

Now, the third embodiment of the syringe according to the presentinvention will be described below referring to these figures. In thefollowing, description will be centered on differences from theabove-described embodiments, and description of the same items as abovewill be omitted.

This embodiment is the same as the first embodiment, except for theconfiguration of the fixing means for fixing the stopper to the pusher.

In this embodiment, plate pieces 44 and 45 of the pusher 4 are providedat their edge portions with ribs extending in the longitudinaldirection, and the ribs constitute racks 442 and 452, respectively.

Of the racks 442 and 452, the surfaces facing a plate piece 46 areprovided with pluralities of engaging recessed portions 443 and 453 at apredetermined interval. In the configuration shown in the figures, theengaging recessed portions 443 and 453 are composed of roughly U-shapedgrooves.

The stopper 5A is composed of a first member 6 and a second member 7.

From a base end wall 615 (see FIG. 4) of the first member 6, engagingportions 67 a and 67 b to be engaged with the racks 442 and 452 areextended in the shape of arms in the tip end direction. The engagingportion 67 a is located between the rack 442 and the plate piece 46, andthe engaging portion 67 b is located between the rack 452 and the platepiece 46.

On tip end portions of the engaging portions 67 a and 67 b, projections671 a and 671 b capable of being inserted into the engaging recessedportions 443 and 453 are formed to project outwards. The projections 671a and 671 b are roughly U shaped (semicylindrically shaped).

An upper wall 613 of the first member 6 is provided with holes 68 a and68 b on both sides of the leaf spring 65.

From the lower surface of an operating portion 71 of the second member7, pressing portions 74 a and 74 b are projected in the form of arms.The second member 7 is disposed on the first member 6 in the conditionwhere the pressing portions 74 a and 74 b are inserted in the holes 68 aand 68 b, respectively. In this mounted state, the pressing portions 74a and 74 b, on the tip end side, are located on the inside of theengaging portions 67 a and 67 b.

At lower end portions of the pressing portions 74 a and 74 b, projectedportions 741 a and 741 b are respectively formed to project outwards. Inaddition, the projected portions 741 a and 741 b are respectivelyprovided with inclined tapered surfaces 742 a and 742 b on the upperside.

In this embodiment, the racks 442, 452, the engaging portions 67 a, 67b, the leaf spring 65 and the pressing portions 74 a, 74 b constitute afixing means for fixing the stopper 5A to the pusher 4.

Normally, the second member 7 is in the state of being lifted (spaced)from the upper wall 613 of the operating portion 71 by a biasing forceof the leaf spring 65, as shown in FIG. 8. When the operating portion 71is depressed with a finger, the second member 7 is displaced downwardsagainst the biasing force of the leaf spring 65, and the lower surfaceof the operating portion 71 makes contact with the upper wall 613, asshown in FIG. 9.

In conjunction with such operations at the operating portion 71, thepressing portions 74 a and 74 b are each displaced between a firstposition shown in FIG. 8 and a second position shown in FIG. 9 which isdeviated downwards from the first position.

When the pressing portions 74 a and 74 b are at their first positions asshown in FIG. 8, i.e., in the condition where the operating portion 71is not depressed, the projected portions 741 a and 741 b are at the samepositions (height) as the engaging portions 67 a and 67 b, pressing theengaging portions 67 a and 67 b outwards. As a result, the engagingportions 67 a and 67 b are respectively displaced outwards, and theprojections 671 a and 671 b are inserted in the engaging recessedportions 443 and 453 of the racks 442 and 452, respectively. Thus, inthe condition shown in FIG. 8, the engaging portions 67 a and 67 b areengaged with the racks 442 and 452, whereby the stopper 5A is fixed tothe pusher 4.

When the pressing portions 74 a and 74 b are at their second positionsas shown in FIG. 9, i.e., in the condition where the operating portion71 is depressed, the projected portions 741 a and 741 b are located onthe lower side relative to the engaging portions 67 a and 67 b, so thatthe pressing on the engaging portions 67 a and 67 b is released. As aresult, the engaging portions 67 a and 67 b are displaced inwards bytheir own elasticity, and the projections 671 a and 671 b are retractedfrom the engaging recessed portions 443 and 453 of the racks 442 and452. Thus, in the condition shown in FIG. 9, fixation of the stopper 5Ais released (canceled), and the stopper 5A can be slid (moved) relativeto the pusher 4.

When the depression on the operating portion 71 is released startingfrom the condition shown in FIG. 9, the second member 7 is displacedupwards by the biasing force of the leaf spring 65, and the pressingportions 74 a and 74 b are returned to their first positions, wherebythe fixed state shown in FIG. 8 is retained. In this instance, theengaging portions 67 a and 67 b can be smoothly returned to thecondition shown in FIG. 8, by being pressed against the projectedportions 741 a and 741 b while sliding on the tapered surface 742 a and742 b.

Thus, in this embodiment, like in the first embodiment, the stopper 5Acan be slid on the pusher 4 and the position of the stopper 5A can beeasily regulated, by depressing the operating portion 71 with a finger.

FOURTH EMBODIMENT

FIGS. 10 and 11 are partly sectional perspective views of a pusher and astopper in a fourth embodiment of the syringe according to the presentinvention. Incidentally, for convenience of description, the side of athird member of the stopper in FIGS. 10 and 11 will be referred to as“upper”, and the side of the pusher as “lower”.

Now, the fourth embodiment of the syringe according to the presentinvention will be described below referring these figures. In thefollowing, description will be centered on differences from theabove-mentioned embodiments, and description of the same items as abovewill be omitted.

This embodiment is the same as the first embodiment, except for theconfiguration of the fixing means for fixing the stopper to the pusher.

In this embodiment, a plate piece 46 of the pusher 4 is provided at itsedge portion with a plurality of engaging recessed portions 462 at apredetermined interval along the longitudinal direction, to constitute arack 461. The engaging recessed portions 462 are composed of roughlyV-shaped notches (grooves), so that the rack 461 is serrate.

The stopper 5B is composed of a first member 6, a second member 8, and athird member 9. In FIGS. 10 and 11, the first member 6 and the secondmember 8 are shown in the state of being cut in the direction orthogonalto the longitudinal direction of the pusher 4, at the center in thelongitudinal direction.

The internal structure of the stopper 5B is symmetrical on the tip endside and the base end side. Namely, while the first member 6 and thesecond member 8 are shown only on the tip end side in FIGS. 10 and 11,the members on the base end side are symmetrical with the members on thetip end side.

The second member 8 includes a plate-like (rod-like) main body portion81, which is disposed in the state of being inserted into a casing 61 ofthe first member 6 from a lateral side. The main body portion 81 isprovided at its end portion with an operating portion 82 which functionsas a pushbutton. Namely, the operating portion 82 is provided on alateral side of the stopper 5B.

The main body portion 81 is provided with a pair of leaf springs 84, 84projecting to the tip end side and to the base end side, respectively.While only the leaf spring on the tip end side is shown in FIGS. 10 and11, the same leaf spring is provided also on the base end side. The leafsprings 84 are formed integrally with the main body portion 81. Tip endportions of the leaf springs 84 are each in contact with an inside wallof the casing 61.

In addition, the main body portion 81 is provided with an engagingportion (projection) 83 capable of engagement with the rack 461, theengaging portion 83 formed to project downwards. The engaging portion 83is edge shaped (V-shaped) in correspondence with the engaging recessedportions 462.

The third member 9 constitutes a cover body for the first member 6, andincludes a roughly plate-like cover portion 91, and a plurality of(four, in the configuration shown in the figures) claw portions 92projected from the lower surface of the cover portion 91. The firstmember 6 (casing 61) is provided with holes 616 respectively atpositions corresponding to the claw portions 92, and the third member 9is mounted to the first member 6 by inserting and fitting the clawportions 92 into the holes 616. Incidentally, while only two holes 616on the tip end side are shown in FIGS. 10 and 11, the first member 6 isprovided with two holes 616 also on the base end side. With the thirdmember 9 mounted to the first member 6, the second member 8 is preventedfrom slipping off from the first member 6.

In this embodiment, the rack 461, the engaging portion 83 and the leafsprings 84 constitute the fixing means for fixing the stopper 5B to thepusher 4.

When the operating portion 82 is not depressed, as shown in FIG. 10, theleft side of the main body portion 81 in the figure is in the state ofbeing projected from the casing 61 by a biasing force of the leaf spring84. In this condition, the engaging portion 83 is located in a positionwhere it is inserted in the engaging recessed portion 462 of the rack461, whereby the stopper 5B is fixed to the pusher 4.

When the operating portion 82 is pressed rightwards in the figurestarting from this condition, the leaf spring 84 is deflected rightwardsand the main body portion 81 is moved so as to sink into the inside ofthe casing 61, as shown in FIG. 11. By this movement of the main bodyportion 81, the engaging portion 83 is retracted to a lateral side ofthe rack 461. As a result, in the condition shown in FIG. 11, thefixation of the stopper 5B is released (canceled), so that the stopper5B can be slid (moved) relative to the pusher 4.

When the depression on the operating portion 82 is released (canceled)starting from the condition shown in FIG. 11, the biasing force of theleaf spring 84 displaces the second member 8 (main body portion 81)leftwards, whereby the fixed state shown in FIG. 10 is retained.

Thus, in this embodiment, like in the first embodiment, the stopper 5Bcan be slid on the pusher 4 in the longitudinal direction of the pusher4 and the position of the stopper 5B can be easily regulated, bydepressing the operating portion 82 with a finger. In this case, sincethe operating portion 82 is provided at the lateral side of the stopper5B in this embodiment, the operating portion 82 can be depressed bypinching the stopper 5B with two fingers from both sides. This ensuresthat, by sliding the stopper 5B while holding (pinching) the stopper 5Bbetween two fingers, the position of the stopper 5B on the pusher 4 canbe regulated, and the operation can be performed more easily.

FIFTH EMBODIMENT

FIG. 12 is an exploded perspective view of a pusher portion in a fifthembodiment of the syringe according to the present invention, and FIG.13 shows perspective views illustrating the operating conditions of astopper attached to the pusher portion shown in FIG. 12. Incidentally,for convenience of description, the side of a head (connection portion)of the pusher in FIGS. 12 and 13 will be referred to as “tip end”, andthe side of a flange-formed finger receiving portion as “base end”.

Now, the fifth embodiment of the syringe according to the presentinvention will be described below. In the following, description will becentered on differences from the above-described embodiments, anddescription of the same items as above will be omitted.

In FIG. 12, the pusher 4 includes a main body portion 40 having theshape of a single plate piece extending in the longitudinal direction,instead of a main body portion having such a shape that plate pieces areintersected in a cross form. On the base end side of the main bodyportion 40, i.e., between a second flange 421 and a flange-formed fingerreceiving portion 401, a pair of rail portions (ribs) 49, 49 are formedintegrally with the main body portion 40 along the longitudinaldirection of the main body portion 40. The rail portion 49, 49 areprovided to be substantially parallel to each other, and guide thestopper 5 which will be described later.

As shown in FIG. 12, the stopper 5 includes a stopper main body 51, anda brake portion 52. The stopper main body 51 and the brake portion 52are each designed to be substantially symmetrical on the left and rightsides.

The stopper main body 51 is provided with a pair of grooves (recessedportions) 511, 511 opening downwards, and the rail portions 49, 49 areinserted in the grooves 511, 511. By a movement of the stopper main body51 along the rail portions 49, 49, the stopper 5 is moved along thelongitudinal direction of the pusher 4.

In addition, the stopper main body 51 is provided at its central portion(between the grooves 511, 511) with a groove (recessed portion) 512opening upwards. A fitting portion 763 formed at a lower portion of thetip end of an operating member 75 which will be described later isfitted in the groove 512.

The stopper main body 51 is provided with a pair of bearings 513, 513 onthe base end side. An end portion of a rotary shaft 77 of an operatingmember 75 which will be described later is inserted in and rotatablyfixed in each of the bearings 513.

The stopper main body 51 is provided at its base end with a pair of flatplate form brake portions 52, 52 which project in the base end directionand are substantially parallel to each other. Each of the brake portions52 is formed integral with the stopper main body 51, and is elasticallydeformed, with its tip end as a fixed end and with its base end as amovable end.

In the condition where the stopper 5 is attached to the main bodyportion 40 of the pusher 4, the brake portions 52 are located on theinside of the rail portions 49, 49, respectively. With each brakeportion 52 (a portion of the stopper 5) pressed against each railportion 49, the stopper 5 is fixed relative to the pusher 4. On theother hand, with each brake portion 52 spaced from each rail portion 49,the fixation of the stopper 5 relative to the pusher 4 is released(canceled). Incidentally, the distance between outer surfaces 521 of thebrake portions 52 (length L, in FIG. 12) is nearly equal to or slightlysmaller than the distance between inner surfaces 491 of the railportions 49 (length M, in FIG. 12). Therefore, in the condition wherethe fixation of the stopper 5 to the pusher 4 is released, the stopper 5can be smoothly moved along the longitudinal direction of the pusher 4.

Thus, in this embodiment, the inner surfaces 491 of the rail portions 49and the outer surfaces 521 of the brake portions 52 constitute contactsurfaces which are pressed against each other. Incidentally, since thepair of rail portions 49 are substantially parallel to each other asabove-described, the pair of the contact surfaces of the pusher 4 aresubstantially parallel to each other and face each other.

In this embodiment, the outer surfaces 521 of the brake portions 52 andthe inner surfaces 491 of the rail portions 49 are both constituted ofrough surfaces. This makes it possible to fix the stopper 5 relative tothe pusher 4 more securely.

In the first to fourth embodiments of the syringe according to thepresent invention in which the stopper is fixed relative to the pusherby the engagement between the engaging recessed portions (or engagingprojected portions) provided in the rack(s) formed on the main bodyportion of the pusher and the engaging projected portion(s) (engagingrecessed portion(s)) provided in the stopper as above-described, theminimum of the amount of the chemical discharged from the syringe (dose)is limited by the interval (pitch) of the engaging recessed portions (orengaging projected portions). On the other hand, the configurationaccording to this embodiment is advantageous in that the minimum of theamount of the chemical discharged from the syringe 1 can be set to besmaller, for example, it is possible to set the dose of the chemicalmore finely.

Incidentally, only one of the outer surface 521 of the brake portion 52and the inner surface 491 of the rail portion 49 (namely, the contactsurfaces of the stopper 5 and the pusher 4) may be constituted of arough surface. In addition, either one or both of the outer surface 521of the brake portion 52 and the inner surface 491 of the rail portion 49may be formed of a material having a high frictional resistance (e.g.,an elastic material such as various rubbers, various thermoplasticelastomers, etc.).

The stopper 5 is provided with an operating member 75 for fixing thestopper 5 relative to the pusher 4, the operating member 75 being soprovided as to be turnable (displaceable).

The operating member 75 includes a main body portion 76, and rotaryshafts 77, 77 projected laterally from the main body portion 76. Therotary shafts 77, 77 are inserted in bearings 513, 513 provided on thestopper main body 51, whereby the operating member 75 is turnablerelative to the stopper main body 51.

The main body portion 76 is a portion to be depressed by a finger, andfunctions as a pushbutton. The main body portion 76 is provided on itsupper surface with a plurality of ribs 761 showing an anti-slippingfunction at the time of depressing the operating member 75 (main bodyportion 76) with a finger.

A wedge portion (fitting portion) 762 projecting downwards is providedat a base end side lower portion of the main body portion 76, integrallywith the main body portion 76. On the other hand, a fitting portion 763projecting in the tip end direction is provided at a tip end side lowerportion of the main body portion 76, integrally with the main bodyportion 76.

The width of the wedge portion 762 (length P, in FIG. 12) is set to beslightly larger than the interval between the inner surfaces 521 of thebrake portions 52 (length N, in FIG. 12). Therefore, when the base endside of the operating member 75 (main body portion 76) is pressed towardthe pusher 4, the operating member 75 is turned relative to the stopper5 with the rotary shaft 77 as a center and the wedge portion 762 isdisplaced downwards, as shown in FIG. 13A. Then, the wedge portion 762(a portion of the operating member 75) is inserted (fitted) between thebrake portions 52, 52, pressing wider the brake portions 52, 52 in thedirections for spacing away from each other. As a result, each brakeportion 52 is clamped between the wedge portion 762 (a portion of theoperating member 75) and the rail portion 49 (pusher 4) and is pressedagainst the pusher 4, whereby the stopper 5 is fixed relative to thepusher 4.

On the other hand, when the tip end side of the main body portion 76 ofthe operating member 75 is pressed toward the pusher 4 starting fromthis condition, the operating member 75 is turned relative to thestopper 5 with the rotary shaft 77 as a center and the wedge portion 762is displaced upwards, as shown in FIG. 13B. As a result, the wedgeportion 762 is released from between the brake portions 52, 52, and thefixation of the stopper 5 relative to the pusher 4 is released(canceled), so that the stopper 5 is slidable (movable) relative to thepusher 4.

In addition, the width of the fitting portion 763 (length Q, in FIG. 12)is set to be larger than the width of the groove 512 in the stopper mainbody 51 (length O, in FIG. 12), so that when the fitting portion 763 isfitted into the groove 512 of the stopper main body 51, the operatingmember 75 is fixed relative to the stopper main body 51 (see FIG. 13B).Therefore, during the operation of moving the stopper 5 in thelongitudinal direction of the pusher 4, the operating member 75 can beprevented from moving (turning) to interfere with the operation.

As has been described above, in the syringe 1 according to thisembodiment, by depressing the operating member 75 (main body portion 76)with a finger, it is possible to fix the stopper 5 to the pusher 4 andrelease the fixation, to slide the stopper 5 on the pusher, and toregulate the position of the stopper 5 to a desired position. Byregulating the position of the stopper 5 on the pusher 4 in this manner,it is possible to change the depth of possible insertion of the pusher 4into the outer tube 2 and, therefore, to set the amount of the chemical100 discharged to a desired amount. Since the pusher 4 (main bodyportion 40) is provided with the graduations 48 corresponding to theamount of the chemical discharged from the syringe 1 as has beendescribed in the first embodiment of the syringe, the desired amount ofthe chemical 100 can be discharged, by pushing in the pusher 4 in thecondition where the position of a tip end face 514 of the stopper 5(stopper main body 51) is regulated to the graduations 48.

Besides, since the pusher 4 is provided with the positioning means(second flange 42) for positioning the stopper 5 to 0 (zero) of thegraduations 48, the stopper 5 can be easily positioned to 0 (zero) ofthe graduations (zero point setting), by moving the stopper 5 in the tipend direction until the tip end face 514 of the stopper 5 abuts on thebase end face 421 of the second flange 42.

SIXTH EMBODIMENT

FIG. 14 is a plan view of a main body portion of a pusher and a stopperin a sixth embodiment of the syringe according to the present invention,FIG. 15 shows partly sectional side views illustrating the operatingconditions of the stopper shown in FIG. 14, FIG. 16 shows sectionalviews along line A-A of FIG. 15, and FIG. 17 shows sectional views alongline B-B of FIG. 15. Incidentally, for convenience of description, theside of a finger receiving portion of the pusher in FIGS. 14 and 15 willbe referred to as “base end”, the opposite side as “tip end”, theviewer's side of the sheet of FIG. 16 will be referred to as “tip end”,and the opposite side (the depth side) of the sheet as “base end”, thelower side in FIG. 17 will be referred to as “tip end”, and the upperside as “base end”.

Now, the syringe according to the sixth embodiment will be describedbelow. In the following, description will be centered on differencesfrom the fifth embodiment, and description of the same items as abovewill be omitted.

The sixth embodiment is the same as the fifth embodiment, except for theconfigurations of the pusher, the stopper, and the operating member.

The pusher 4 in the sixth embodiment includes a main body portion 40which has a shape such that two plate pieces 45 and 46 are intersectedin a cross form.

At an upper edge portion of the plate piece 46, a plate piece form railportion 49 is provided substantially in parallel to the plate piece 45.The rail portion 49 is formed integral with the pusher 4.

As shown in FIG. 16, the stopper 5 includes a stopper main body 53composed of two members 53 a, 53 b, and a brake portion 54.

The stopper main body 53 is provided with a groove (recessed portion)531 opening downwards. The rail portion 49 is inserted in the groove531. With the stopper main body 53 moved along the rail portion 49, thestopper 5 is moved in the longitudinal direction of the pusher 4.

The stopper main body 53 is provided on its upper surface with aplurality of ribs 532 showing an anti-slipping function at the time ofsliding the stopper 5 (stopper main body 53) with a finger.

These ribs 532 are provided with a pair of recessed portions 533 at bothside portions thereof. Each recessed portion 533 is for securing an areafor printing or labeling as an indication for easy discriminationbetween the condition where the stopper 5 is fixed and the conditionwhere the fixation is released (canceled). Besides, the recessed portion533 may have a surface projected or recessed in the shape of charactersor symbols, or may have a surface decorated by printing or the like.

Four circular arc-shaped leg portions 534 are provided at lower portionsof the stopper main body 53. Each leg portion 534 is elasticallydeformable. Provision of the leg portions 534 ensures that, at the timeof moving the stopper 5 relative to the pusher 4, the pusher 5 can beprevented from chattering relative to the pusher 4, and the operationcan be performed more securely.

At lower portions of the stopper main body 53, a pair of flat plate-likebrake portions 54, 54 projecting inwards are provided substantially inparallel. Each brake portion 54 is formed integral with the stopper mainbody 53 (53 a or 53 b). In this configuration, the stopper 5 is providedso as to cover the rail portion 49 (see FIG. 16).

With each brake portion 54 pressed against the rail portion 49, thestopper 5 is fixed relative to the pusher 4 (the condition shown in FIG.15A and FIG. 16A).

On the other hand, with each brake portion 54 spaced from the railportion 49, the fixation of the stopper 5 relative to the pusher 4 isreleased (canceled) (the condition shown in FIG. 15B and FIG. 16B). Inthis condition, the stopper 5 can be smoothly moved along thelongitudinal direction of the pusher 4.

Thus, in this embodiment, lower surfaces 492 of both end portions (leftand right end portions, in FIG. 16) of the rail portion 49 and uppersurfaces 541 of the brake portions 54 constitute contact surfaces whichare pressed against each other. Incidentally, since the rail portions 49are plate piece-formed as above-mentioned, a pair of the contactsurfaces on the side of the pusher 4 are provided to be substantiallyparallel and are provided on the same plane.

The upper surfaces 541 of the brake portions 54 and the lower surface492 are both constituted of rough surfaces, in the same manner as in thefifth embodiment. This makes it possible to fix the stopper 5 relativeto the pusher 4 more securely.

Incidentally, only one of the upper surface 541 of the brake portion 54and the lower surface 492 of the rail portion 49 (namely, the contactsurfaces of the stopper 5 and the pusher 4) may be constituted of arough surface. In addition, either one or both of the upper surface 541of the brake portion 54 and the lower surface 492 of the rail portion 49may be formed of a material having a high frictional resistance (e.g.,an elastic material such as various rubbers, various thermoplasticelastomers, etc.).

In the stopper 5, an operating member 75 for fixing the stopper 5relative to the pusher 4 is provided to be slidable (displaceable) inthe width direction of the pusher 4.

The operating member 75 includes a plate-like (or rod-like) main bodyportion 78, and is disposed in the condition where the main body portion78 is inserted between the stopper main body 53 and the rail portions 49from a lateral side. At both end portions (both left and right endportions, in FIGS. 16 and 17) of the main body portion 78, operatingportions 79 each functioning as a pushbutton are provided.

Incidentally, as shown in FIG. 17, a pair of wedge portions (fittingportions) 781 are projected from both end portions (upper and lowerportions, in FIG. 17) of the main body portion 78. On the other hand, apair of thick portions 535 are projected from the surface of the stoppermain body 53 on the side of a groove 531 (see FIG. 16). Each wedgeportion 781 and each thick portion 535 are provided at substantially thesame position, in the longitudinal direction of the pusher 4.

The thickness of the wedge portion 781 is set to be slightly greaterthan the distance over which the stopper main body 53 can be movedrelative to the pusher 4 in the thickness direction of the wedge portion781 (the direction perpendicular to the longitudinal direction of thepusher 4). Therefore, when the operating portion 79 on one side (theleft side, in the configuration shown in the figures) of the operatingmember 75 is pressed toward the pusher 4, the operating member 75 isslid (displaced) rightwards relative to the stopper 5, and the wedgeportion 781 is fitted between the thick portion 535 (stopper main body53) and the rail portions 49, whereby the stopper main body 53 is movedin the direction of spacing away from the pusher 4. In this instance,each brake portion 54 approaches the rail portion 49, and each brakeportion 54 is pressed against the rail portion 49, whereby the stopper 5is fixed relative to the pusher 4 (see FIGS. 15A, 16A, and 17A).

On the other hand, when the operating portion 79 on the other side(right side, in the configuration shown in the figures) of the operatingmember 75 is pressed toward the pusher 4 (is pushed back reversely tothe above) starting from this condition, the operating member 75 is slid(displaced) leftwards relative to the stopper 5, and the wedge portion781 is released from between the thick portion 535 (stopper main body53) and the rail portion 49. As a result, the fixation of the stopper 5relative to the pusher 4 is released (canceled), and the stopper 5 isslidable (movable) in the longitudinal direction of the pusher 4.

In addition, the surfaces of the wedge portion 781 and the thick portion535 which face each other in the condition where the fixation of thestopper 5 relative to the pusher 4 is released (canceled) are inclinedsurfaces 781 a and 535 a, respectively. This ensures that the operationof fitting the wedge portion 781 between the thick portion 535 (stoppermain body 53) and the rail portion 49 can be performed more smoothly andsecurely.

In the syringe 1 according to the sixth embodiment, the depth ofinsertion of the pusher 4 into the outer tube 2 is restricted by theabutment of a tip end face 536 of the stopper 5 (stopper main body 53)on the base end portion 28 of the outer tube 2.

In addition, a pair of roughly L-shaped arm portions 537 are provided atthe tip ends of the stopper 5. Each arm portion 537 is formed integralwith the stopper main body 53 so as to project in the tip end directionfrom the tip end of the stopper main body 53. In the same manner as inthe fifth embodiment, the base end face 421 of the second flange 42 islocated at a position corresponding to 0 (zero) of the graduations 48,and the stopper 5 can be easily adjusted to 0 (zero) of the graduations48 (zero point setting), by moving the stopper 5 in the tip enddirection until the tip end of each arm portion 537 abuts on the baseend face 421 of the second flange 42. Namely, in this embodiment, eacharm portion 537 and the second flange 42 constitute the positioningmeans for positioning the stopper 5 to 0 (zero) of the graduations 48.

With the syringe 1 according to the sixth embodiment, also, the samefunctions and effects as those of the syringe 1 according to the fifthembodiment can be obtained. Besides, the syringe 1 according to thesixth embodiment can be used in substantially the same manner as thesyringe 1 according to the fifth embodiment.

SEVENTH EMBODIMENT

FIG. 18 is an exploded perspective view of a pusher portion in a seventhembodiment of the syringe according to the present invention.Incidentally, for convenience of description, the side of a head(connection portion) of the pusher in FIG. 18 will be referred to as“tip end”, and the side of a flange-formed finger receiving portion as“base end”.

Now, the syringe according to the seventh embodiment will be describedbelow. In the following, description will be centered on differencesfrom the fifth and sixth embodiments, and description of the same itemsas above will be omitted.

The seventh embodiment is the same as the fifth embodiment, except forthe configurations of the contact surfaces of the stopper and thepusher.

As shown in FIG. 18, each brake portion 52 is composed of an innermember 52 a formed integral with a stopper main body 51, and an outermember (pad 52 b) attached (fixed) to the outside (the side facing theinner surface 491 of a rail portion 49) of the inner member 52 a. Theouter member 52 b is formed of an elastic material. In other words, theouter surface 521 of each brake portion 52 (the contact surface on theside of the stopper 5) is constituted of a material having a highfrictional resistance.

Examples of such a material include various rubber materials such asnatural rubber, butyl rubber, isoprene rubber, butadiene rubber,styrene-butadiene rubber, silicone rubbers, etc., various thermoplasticelastomers based on polyurethane, polyester, polyamide, olefin, styreneor the like, and mixtures thereof.

On the other hand, the inner surface 491 of each rail portion 49 isprovided with a plurality of recessed portions 491 a at a predeterminedinterval. In this embodiment, the recessed portions 491 a are composedof substantially V-shaped grooves.

This configuration ensures that, when the base end side of an operatingmember 75 (main body portion 76) is pressed toward the pusher 4, a wedgeportion 762 (a portion of the operating member 75) is inserted (fitted)between the brake portions 52, 52, to press wider the brake portions 52,52 in the directions for spacing away from each other. As a result, theouter member 52 b formed of the elastic material of each brake portion52 is pressed against the recessed portions 491 a of the rail portion49, whereby the stopper 5 is fixed relative to the pusher 4.

Incidentally, the shape of the recessed portions 491 a is not limited toV shape; for example, the recessed portions 491 a may be U-shaped,roughly angular U-shaped, semicircular, or holes or the like.

Other than the configuration shown in the figure, a configuration inwhich the outer surface 521 of each brake portion 52 is provided withrecessed portions and the inner surface 491 of each rail portion 49 isformed of an elastic material may also be adopted, and both the outersurface 521 of each brake portion 52 and the inner surface 491 of eachrail portion 49 may be formed of an elastic material.

With the syringe 1 according to the seventh embodiment, also, the samefunctions and effects as those of the syringe 1 according to the fifthembodiment can be obtained. In addition, the syringe 1 according to theseventh embodiment can be used in substantially the same manner as thesyringe 1 according to the fifth embodiment.

While the syringe according to the present invention has been describedreferring to the embodiments shown in the figures, the present inventionis not limited to the embodiments. Each of the portions constituting thesyringe can be replaced by one having an arbitrary configuration andbeing capable of displaying a function equivalent to theabove-mentioned.

Besides, in the present invention, arbitrary two or more of theconfigurations according to the above-described embodiments may becombined.

INDUSTRIAL APPLICABILITY

As has been described above, according to the present invention, anaccurate amount of a liquid can be discharged by a simple operation, andsuch a mistake that the discharge amount would be excessive orinsufficient can be securely prevented from occurring.

In addition, it is possible to release (cancel) the fixation of astopper and regulate the position of the stopper on a pusher by a simpleoperation of only pressing, pulling or pinching an operating portion,and, therefore, the operation of setting the amount of a liquid to bedischarged can be performed extremely easily and swiftly.

Besides, when a configuration in which a fixing means for the stopper iselastically returned to a fixation condition upon release of anoperation on the operating portion is adopted, the stopper isautomatically returned to the fixed state, so that the position of thestopper once set can be prevented from being deviated to produce anerror in the set discharge amount.

In addition, when a configuration in which the stopper is fixed relativeto the pusher by pressing a portion of the stopper against the pusher isadopted, either one or both of the contact surfaces of the stopper andthe pusher may be constituted of rough surfaces or formed of a materialhaving a high frictional resistance, whereby the minimum of the amountof a liquid discharged can be set at a smaller value. This isadvantageous, for example, in that the dose of a chemical can be setmore finely, and is therefore suitable for dosing a required amount of achemical while performing a fine adjustment, as in the case of dosing anantitumor agent.

Besides, in the operation of discharging a liquid, the above-mentionedeffects can be attained by a simple operation of only moving the pusherin the tip end direction until the stopper abuts on the outer tube, sothat the pusher can be operated without need for subtle regulation offorce, which promises excellent operationality.

1. A syringe comprising: an outer tube, a gasket slidable in said outertube, a pusher inserted through an opening of a base end of said outertube and operable for moving said gasket, a stopper disposed on saidpusher to be slidable along the longitudinal direction of said pusher,fixing means for selecting and fixing the position of said stopper onsaid pusher, an operating portion provided in said stopper forperforming a pressing operation, a traction operation or a pinchingoperation, wherein the position of said stopper on said pusher can beregulated by releasing the fixation by said fixing means through anoperation at said operating portion, wherein the depth of insertion ofsaid pusher into said outer tube is restricted by abutment of saidstopper on a portion of said outer tube, wherein said fixing means isreturned to a fixation state by elasticity when the operation on saidoperating portion is released, wherein said fixing means comprises arack provided on said pusher and including a plurality of engagingrecessed portions or engaging projected portions provided at apredetermined interval along the longitudinal direction of said pusher,and an engaging portion provided on said stopper to be displaceablebetween a state of being engaged with said rack and a state of beingretracted from said rack, said engaging portion is normally engaged withsaid rack and is retracted from said rack by an operation at saidoperating portion, wherein said fixing means comprises a pressingportion operated in conjunction with said operating portion to bedisplaced between a first position for pressing said engaging portion tobe engaged with said rack and a second position for releasing thepressing, and biasing means biasing said pressing portion to bring intosaid first position, and said fixing means is normally in such a statethat said pressing portion is located in said first position and saidengaging portion is engaged with said rack to fix said stopper, saidfixing means being so operated that, when said operating portion isoperated, said pressing portion is moved to said second position,whereby said engaging portion is retracted from said rack and a fixationof said stopper is released, and when the operation on said operatingportion is released, said fixing means is returned into the state forfixation of said stopper by the biasing force of said biasing means. 2.A syringe as set forth in claim 1, wherein said pusher comprises a mainbody portion in such a shape that plate pieces are intersected in across form, and said rack is formed in a portion of said plate pieces.3. A syringe as set forth in claim 1, wherein said pusher comprises arail portion, and said stopper comprises a slide portion slid along saidrail portion, and said stopper is slid along the longitudinal directionof said pusher by guiding of said slide portion on said rail.
 4. Asyringe as set forth in claim 1, wherein said pusher is provided thereonwith graduations for indicating the position of said stoppercorresponding to the amount of liquid discharged.
 5. A syringe as setforth in claim 1, wherein said pusher is provided thereon withgraduations for indicating the position of said stopper corresponding tothe amount of liquid discharged, and wherein said pusher comprisespositioning means for positioning said stopper at the position of 0(zero) of said graduations.
 6. A syringe as set forth in claim 1,wherein a chemical is preliminarily contained in a space surrounded bysaid outer tube and said gasket.
 7. A syringe comprising: an outer tube,a gasket slidable in said outer tube, a pusher inserted through anopening of a base end of said outer tube and operable for moving saidgasket, a stopper disposed on said pusher to be slidable along thelongitudinal direction of said pusher, fixing means for selecting andfixing the position of said stopper on said pusher, an operating portionprovided in said stopper for performing a pressing operation, a tractionoperation or a pinching operation, wherein the position of said stopperon said pusher can be regulated by releasing the fixation by said fixingmeans through an operation at said operating portion, wherein the depthof insertion of said pusher into said outer tube is restricted byabutment of said stopper on a portion of said outer tube, wherein saidfixing means is returned to a fixation state by elasticity when theoperation on said operating portion is released, wherein said fixingmeans comprises a rack provided on said pusher and including a pluralityof engaging recessed portions or engaging projected portions provided ata predetermined interval along the longitudinal direction of saidpusher, and an engaging portion provided on said stopper to bedisplaceable between a state of being engaged with said rack and a stateof being retracted from said rack, wherein said engaging portion isnormally engaged with said rack and is retracted from said rack by anoperation at said operating portion, wherein said fixing means comprisesbiasing means biasing said engaging portion to displace from a state ofbeing retracted from said rack to a state of being engaged with saidrack, said fixing means is normally in such a state that said engagingportion is engaged with said rack to fix said stopper, and said fixingmeans is so operated that, when said operating portion is operated, saidengaging portion is retracted from said rack to release a fixation ofsaid stopper, and when the operation on said operating portion isreleased, said fixing means is returned into the state for fixation ofsaid stopper by the biasing force of said biasing means.
 8. A syringe asset forth in claim 7, wherein said pusher comprises a main body portionin such a shape that plate pieces are intersected in a cross form, andsaid rack is formed in a portion of said plate pieces.
 9. A syringe asset forth in claim 7, wherein said pusher comprises a rail portion, andsaid stopper comprises a slide portion slid along said rail portion, andsaid stopper is slid along the longitudinal direction of said pusher byguiding of said slide portion on said rail.
 10. A syringe as set forthin claim 7, wherein said pusher is provided thereon with graduations forindicating the position of said stopper corresponding to the amount ofliquid discharged.
 11. A syringe as set forth in claim 7, wherein saidpusher is provided thereon with graduations for indicating the positionof said stopper corresponding to the amount of liquid discharged, andwherein said pusher comprises positioning means for positioning saidstopper at the position of 0 (zero) of said graduations.
 12. A syringeas set forth in claim 7, wherein a chemical is preliminarily containedin a space surrounded by said outer tube and said gasket.